Improved turn-table



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JOHN L. PIPER, 0F PITTSBURG, PENNSYLVANIA.

Letters .Patent No. 97,440, dated November 30, 1869.

IMPROVED TURN-TABLE.

The Schedule referred to in these Letters Patent and making part of the same4 To all whom 'it may concern.:

Figure 2 is a longitudinal vertical section thereof,

formed by a plane passing through the axis thereof;

Figure 3 is a sectional plan view, formed by a plane passing horizontally through the cap, just below the main girder-beam; and

Figure 4 is a like view, as formedby a plane passing horizontally through the friction-balls, which are the main support of the table.

Like letters of reference indicate like parts in each.

The nature of my invention consists in the construction of improved devices `for operating turntables for railroads, swinging or` drawbridges, 85e, as hereinafterdescribed.`

To enable others skilled in the art to rmake and use my invention, I will proceed to describe its construction and mode of operation.

On any suitably-constructed bed or foundation, I fix the main or central pier or pedestal b, of any desirable size and shape, the upper end, however, terminating in a pivoting-stern, b', of suicient length to extend 11p through the girderV or main beam jl Around the base of the stem b', the pedestal widens ut into a broad, flat circular disk or plate, a..

On the stem blv is placed a cap, c, chambered out on its under side, or made with a cylindrical iiange, c', projecting downward around its outer edge, suiiiciently far tohold in place the balls a', which are placed between it and the plate a., in acontinuous series, and also suii'iciently far'to exclude, as effectually as possible, the dirt from getting in between the cap c and plate c.

At the same time, the cap c and plate a, to avoid loss by friction, should not work in contact with each other.

The cap is also cast with au, annular concavity or concave-faced groove, e, on its under face, near its outer edge, for a track, the face of which works on the upper faces of the SphericaLba-lls c'.

'lhe radius of coneavity of 'the groove e should be, at least, equal to the radius of the balls a', and prefer- Iably, to save friction, I use a longer radius in the former case than in the latter.

The balls c are made of cast-metal, solid or hollow, and of a uniform spherical size.

The hole through the cap c for the stem b is slightly larger than the stem bi.

To reduce to a minimum the friction of the cap c on the stem b', I chamber out the cap c, ou its upper face, for a uniform distance around its centre, leaving a shoulder, e', which forms the boundary of a chamber, and in this chamber place a series of flat circular disks, s, of such diameter, that while one edge of each plays against the shoulder e', the opposite edge will work against the stem b.

Since, as presently ,to be described, the cap c supports the girder-beam trusses and'track or road-bed, e

I avoid all sliding friction by the construction described.

All vertical pressure comes on the balls a', andall lateral strain is received by the disks s. And I not only reduce friction to a minimum, but so construct the devices described that the cap c cannot tip or wabble.

I thus secure a perfectly solid support for the'turntable, aswell as one easily operated, substantial, and durable.

The main girder f, made in, any desirable way, or

' of any known form, also passes ovcrfthc` stem b.'

In building the turn-table, the girder f should extend across the main track or roadway. Then, on its opposite ends, I hang the trussesy not shown in the drawings, on which the track is laid.

v I have described what I consider the best mode of construction, but some changes may be made without at all changing the nature the invention.

The concave track e may, if so preferred, be made on the face of the disk a', though it'would be more liable, in that case, to accumulate dirt, to prevent thev free operation of the balls. Also, the chamber in the upper face of the capo, which holds the disks sn1a v be made deeper, so as to admit spherical balls in lieu ofthe disks. The operation in either case would be the same.

The disks s are covered and held in place by a cap, d.

The stem b may be cast as a part of the pedestal, or otherwise rigidly attached thereto. Y

What I claim as my inventibn, and desire to secure JOHN L. PIPER. 

